blood is found in the uterine cavity; the menstrual clot is formed during Stage VII, and the torn mucosa is healed in the final, Stage VIII.
Histology.—The uterus consists of an internal mucosa and external muscular layers ; the mucosa is composed of uterine and glandular epithelium, blood vessels, and stroma. The uterine epithelium lines the surface of the stroma, the glandular epithelium lines pits in the stroma and is continued into branches of those pits which extend from their lower end into the deeper part of the stroma.
The stroma itself is a delicate connective-tissue-like layer; the internuclear protoplasm is drawn out into delicate processes which form a continuous network, and there is no intercellular substance.
The histological changes which take place during the menstruation of Macacus rhesus are very similar to those which I have already described in a former paper, “ The Menstruation of entellus (‘ Roy. Soc. Proc.,’ vol. 54, and 4 Philosophical Transactions,’ yol. 185). Work similar to that which I have already described for S. entellus has been undertaken for Macacus rhesuand the phenomena compared step by step. While it has been thought advisable to note the points of similarity and of diffei’ence which occur in the menstruation of these two species, and to point out the fact that the results arrived at by the study of the menstruation of Macacus rhesus entirely confirm the results which my examination of S. entellus led me to publish, I have purposely avoided all unnecessary repetition and have been obliged in consequence to assume some knowledge of the details given in my former papers. It is all the more important to publish this account, as the results which I have arrived at differ in some important particulars from the accounts of menstruation which have been generally accepted.
Stage I. The mucosa of Macacus rhesus is thicker and the protoplasmic network denser, the glands more numerous and more branched than is the case in S. entellus. I find no radial fibres. Stage I.—There is a great increase in the number of nuclei by amitotic division and fragmentation. Hyperplasia occurs. The mucosa becomes much swollen. Stage I.The vessels increase in number and size, and they are congested. There is an increase of leucocytes. Stage I V.— Hypertrophy of the walls of the vessels in the superficial part of the mucosa, followed by degeneration, occurs; the small vessels break down and extravasation of blood takes place. There is no sign of the migration of leucocytes. Stage V. Lacunae are formed at first some distance below the epithelium, but they gradually displace the intervening tissue and come to lie directly below the uterine epithelium.
